The present invention relates to lighting devices, and more particularly, to illumination devices adapted to provide high intensity lighting.
A known problem with using typical prior art lights in high intensity applications is that the lights consume large quantities of power and generate excessive heat in comparison to other lighting devices. These applications thereby suffer not only from higher operating costs and limited portability due to the devices large power consumption, but also can become susceptible to premature failure due to the prolonged exposure to excessive heat.
The invention mitigates the above-described problems by providing high intensity lighting devices that employ a reflective member and a linear light source, which by way of example can be a gas discharge lamp, such as a fluorescent lamp, a mercury vapor lamp, or a neon lamp, or a linear incandescent lamp. The linear light source and reflective member typically share a common axis that extends through their lengths.
More specifically, the present invention provides a lighting device having a high luminous intensity. The lighting device comprises a linear light source, a reflective member, and a translucent region. Preferably, the reflective member is shaped and sized to securely engage the linear light source and the translucent region. which is typically transparent. In this design, the lighting device may be sealed from moisture and contaminants and may be shielded from shock.
In one aspect of the invention, the reflective member comprises a reflector having at least three polygonal-shaped sides. The reflector is preferably located near the ends of the linear light source to direct rays of light toward an intermediate translucent region. In alternative embodiments, the reflective member may include more than one reflector, and each reflector may have a generally conical shape. The generally conical shape may comprise circular, triangular, elliptical, parabolic, and other cross-sectional shapes to control the transmission pattern of light. Preferably, when the reflector has circular cross-sections, its smallest circular cross-section is positioned adjacent to an end of the linear light source.
The above-described reflective member may comprise a specular or a diffuse reflector. Preferably, the reflective member further comprises a coating or reflective film, such as a silver reflective film. A coating or reflective film offers the advantage of reflecting light with minimal absorption which further increases the luminosity of the lighting device.
In another aspect of the invention, the translucent region has a substantially cylindrical shape with a central axis typically coincident with the common axis of the linear light source and the reflective member. Alternatively, the translucent region can have a number of circumferential lengths or arcs. Lenses may also be used in this aspect of the invention so that rays of light incident on the translucent region are refracted into an array of substantially parallel light rays emitted from the lighting device.
In yet another aspect of the invention, the translucent region may comprise a plurality of prisms. In one exemplary embodiment, prismatic light reflective material comprised of a plurality of substantially prism like members refract light at different angles to emit an array of substantially parallel light rays from the lighting device. These transmissive prisms refract light traveling in many different directions to produce a highly luminous collimated array of light.
The reflective member has a substantially total internal reflectance (TIR) so that substantially all of the light produced by the light source is emitted from the lighting device through the translucent region, and is preferably collimated by a lens unitarily formed or interconnected with the translucent region. The axial length of the translucent region may comprise only a small portion of the total axial length of the light source, such as on the order of one to seventy five percent, with ten to fifty percent being preferred. Nevertheless, substantially all of the light produced by the light source is emitted only through the translucent region, resulting in a high intensity lighting device.
The disclosed devices consume little power and do not produce excessive heat in comparison to known lighting devices. The reflective members can be shaped and sized to a variety of linear light sources so that a variety of lights can be created from few parts, rendering a highly adaptable technology that is economical to operate and inexpensive to construct. These features as well as other advantages of the invention will become apparent upon consideration of the following detailed description and accompanying drawings of the embodiments of the invention described below.